How to improve the reliability of PCB equipment

Technical measures to improve the reliability of PCB equipment: scheme selection, circuit design, circuit board design, structure design, component selection, production process, etc., specific measures are as follows:

(1) Simplified scheme design.

In the scheme design, on the premise of ensuring that the equipment meets the technical and performance indicators, the design should be simplified as far as possible, simplifying the circuit and structure design, so that each component becomes the simplest design. The popular modular design method is an effective measure to improve the reliability of equipment. Block function is relatively simple, the system is composed of modules, can reduce the complexity of design, design standardization, normalization. A lot of facts at home and abroad have proved that modular design method should be adopted in product design.

(2) Adopt modules and standard components.

Modules and standard parts are products that have been proved to be highly reliable after a lot of tests and extensive use, which can fully eliminate the defects and hidden dangers of equipment, and also bring convenience for replacement and repair after problems occur. The use of modules and standardized products can not only effectively improve the reliability of equipment, but also greatly shorten the development cycle, and provide very favorable conditions for the rapid modification and installation of equipment.

(3) Improve the integration degree.

Choose a variety of functional, high integration of large-scale, ultra-large scale integrated circuits, as far as possible to reduce the number of components. The fewer components there are, the fewer hidden dangers there are. In this way, not only can improve the reliability of the equipment, but. Can shorten the research and development cycle.

(4) Derating design.

Derating design refers to that components work under conditions lower than their rated stress, which is an effective method to reduce the failure efficiency of components. Therefore, in the premise of ensuring technical performance indicators, the working voltage range, temperature characteristics and electrical characteristics parameters of components are derated, so as to reduce the failure efficiency of components under various stress conditions.

Derating design, different components to consider the factors are different: some voltage range, some current size, some temperature, some frequency, some vibration and so on. In general, the voltage, frequency and temperature characteristics of the capacitor, the power of the resistance, the current and frequency characteristics of the inductor, the junction current, junction temperature or fan out coefficient of the diode, the transistor, the thyristor, the operational amplifier, the driver, the gate circuit and other devices, the switch of the power supply and the voltage/current and temperature resistance of the main power supply source cable, the frequency characteristics of the signal cable, As well as the use of radiator, connector, module power supply and other devices, require derating design.

(5) Select high-quality devices.

Component is the basic unit of equipment, its quality will directly affect the reliability of equipment. Military communication equipment should try to use industrial grade or above products, preferably military products, and strictly carry out aging screening before the machine, eliminate early failure devices.

(6) Make full use of software resources.

Due to the flexibility of software programming, software resources should be fully utilized in the design. At present, there are relatively many debugging means and tools for software, so it is easy to locate faults and design problems, and the solution cycle is relatively short. Making full use of software resources is an important method to improve reliability.

(7) Reliable structure, mature and advanced technology.

In circuit and structure design, the number of connectors and metallized holes should be reduced as far as possible. Circuit devices and chips should be welded directly on the printed board as far as possible. Surface mount devices and surface mount technology should be used to avoid bad contact and ensure the reliability of equipment.

(8) Thermal design.

Excessive temperature is one of the most important factors that may degrade device performance and reliability. Therefore, thermal protection measures should be taken to control and reduce the temperature rise of the device to ensure proper heat dissipation and improve the thermal reliability of the device.

The device performance and reliability deteriorates when the ambient temperature is too low. Some components cannot work properly when the ambient temperature is too low. Therefore, equipment used in low temperature environment should also be tested for low temperature. In the design must consider the equipment working temperature conditions and environment.

(9) Electromagnetic compatibility design.

There are many electromagnetic fields that interfere with the operation of equipment, both natural and man-made. Military equipment is even more so. In modern high-tech electronic resistance, a very important technical means is to locally emit high energy electromagnetic wave to destroy the components in the other party's equipment, so as to make the equipment malfunction. Therefore, effective anti-interference measures such as shielding and filtering should be taken to prevent the interference of noise, interference and electromagnetic field on the equipment to ensure the reliable operation of the equipment.

(10) Anti-vibroflot design.

Equipment in the use, transportation process will be affected by a variety of vibration, impact, thus affecting its reliability, so should improve the mechanical strength and stiffness of the equipment, and take vibration damping buffer measures, in order to strengthen the ability of the equipment to resist vibration, impact, improve the reliability of equipment.

(11) Use fault indicating device.

Design fault detection circuit and fault alarm device, so as to find the fault in time, so as to shorten the time of equipment troubleshooting.

(12) Simple operation and convenient maintenance.

The operation and maintenance function of equipment is one of the main factors to ensure the reliability of equipment. In the design, the insertion unit and module should be used as far as possible, and the modular, standardized structure and quick disassembly structure should be used to facilitate the operation and maintenance. It has been proved that the modular structure of the equipment can greatly simplify operation and facilitate maintenance.